Carbohydrates

Carbohydrates - How they affect Human Health

The foods we eat contain nutrients that provide energy and other things the body needs.
These nutrients fall into three major groups; carbohydrates, fats and proteins and three minor groups; vitamins, minerals and water.

The primary function of Carbohydrates

The primary function of Carbohydrates is to provide energy for all cellular activities performed by the various organs and systems of the body, especially the brain and the nervous system.

The three main Classes of Carbohydrates

The three main Classes of Carbohydrates are

1. Simple carbohydrates / Sugars

Simple carbohydrates have one or two sugars. They are called simple sugars because they contain either natural sugar or added sugar. They taste sweet; usually contain sweeteners such as honey, sugar, molasses or corn syrup. Simple carbohydrates with single sugars include; fructose (found in fruits) and galactose (found in milk products).
Simple carbohydrates with double sugars include: lactose (found in dairy), maltose (found in certain vegetables and in beer) and sucrose (table sugar)
NB: Honey is a double sugar but contains a small amount of vitamins and minerals.
Note: research indicates that honey should not be given to children under 1 year due to the possible presence of a bacterium that causes nervous and respiratory problems present in untreated honey.

2. Complex carbohydrates / Starches

Complex carbohydrates have three or more sugars. They are called starches because they are starchy in nature. They are often healthier than simple carbohydrates because they also provide some dietary fiber.
Complex carbohydrates that occur naturally in starchy foods include; legumes (beans, peas, nuts, and lentils), starchy vegetables (potatoes, yams, and plantains), and whole-grains (breads, cereals and grains).
Complex carbohydrates in refined foods include; biscuits, pastries, cakes, processed, refined or polished cereals and grains.
NB: It is healthiest to eat carbohydrates that contain vitamins, and other nutrients from whole grains instead of polished, processed or refined ones.

3. Fiber

Fiber, though categorized as a complex carbohydrate, does not act like the simple and complex carbohydrates.

Fiber can not be broken down into sugars because the body can not completely digest it.

Fiber helps to

• Regulate blood glucose levels because it does not convert to sugar.
• Lower bad cholesterol levels because it is able to absorb the fatty content of food and excreted together with the faecal matter.
• Promotes regular digestion and excretion of waste because its spongy nature which forms the bulk of the faeces is able to hold water and soften the waste product, making it easy to move through the bowel at a faster rate.
• Helps to control appetite because its bulkiness produces satiety (a feeling of fullness) thus suitable for healthy weight management.

Dietary fiber-rich foods include; whole grains, most fruits and vegetables, including dark leafy green and orange-colored fruits and vegetables.

• NB: refined foods lack fiber.
• Whole grains are a preferred choice
• The natural ones are the healthiest.

Refined sugars;

• Provide calories, but lack vitamins, minerals, and fiber. They are "empty calories" that cause weight gain.
• Most refined foods, like white flour, sugar, and rice, lack vitamin B and other important nutrients unless they are fortified.

Carbohydrate Metabolism

In carbohydrate metabolism, an enzyme called amylase helps break down carbohydrates into blood sugar (glucose).
The Glucose is transported through the blood to the cells and converted into energy. The pancreatic gland in the abdomen then secretes the hormone insulin, which controls the absorption of glucose by the cells. Any excess glucose is converted into glycogen and stored in the liver or as fat in the body’s fatty tissues.
When the body needs more energy, a second hormone called glucagon is secreted by the pancreas. This converts the glycogen back into glucose, released into the blood stream for the cells to use.
The slower the release of glucose and hormones, the more stable and sustainable the energy levels of the body. Complex carbohydrates provide a slower and more sustained release of energy than simple carbohydrates.

Excessive intake of Carbohydrates may lead to

• Weight Gain
  Too much carbohydrate means too much calories. This stimulates the release of larger amounts of insulin to move the excess blood sugar into the cells, where it is stored as fat.
• High Blood Sugar Levels
  During digestion, carbohydrates convert to glucose. The more carbohydrates eaten, the higher the level of glucose.
• Large amounts of insulin are released by the pancreas to control the increased blood sugar levels. With time, the pancreas becomes weak and fails to produce insulin. This results in high blood sugar levels and uncontrolled diabetes.
• High LDL (BAD) Cholesterol Levels
  Most foods high in sugar are also prepared with fat. Such hidden fats and oils may contribute to the high LDL Cholesterol level.
• Tooth Decay
  When too much simple carbohydrates (sugar) is eaten too often, coupled with bad dental care, the bacteria that exist in the mouth tend to enjoy the food debris and in turn erode or eat up the gum causing tooth decay or dental carries.

Carbohydrate Deficiency Effects

• Malnutrition
  Not getting enough carbohydrates can cause malnutrition because most carbohydrate foods are also rich sources of other nutrients.
• Ketosis
  With a low carbohydrate diet, the body tries to compensate for the sudden lack of fuel. The body then goes into ketosis, (a state in which fat and protein are burned for fuel instead of carbohydrate) where the body produces compounds called ketones. This body chemistry changes lead to mood swings, nausea, dizziness, weakness and / or depression.
• Bad Breath
  The ketones can show up in the saliva and cause bad breath.
• Chronic Health Problems
  As the levels of ketones rise in the bloodstream, the blood can become more acidic, placing stress on the kidneys and other organs.
• Impaired Thinking
  Thinking becomes impaired as the brain runs out of glucose to fuel its normal activity.
• Drastic Weight Loss
  Prolonged carbohydrate deficiencies can result in drastic weight loss since the body falls on its fat and protein stores for energy.
• Pre-mature Aging/ Wrinkles
  Long term deficiency breaks down muscle tissue to act as fuel.
• Reduced Energy Levels
  Since carbohydrates provide the body with energy, a deficiency means reduced energy levels.
• Poor Response To Treatment
  Reduced energy levels leave the body unable to work correctly to fight off diseases and heal wounds.
• Constant Fatigue and Weakness
  A deficiency in carbohydrates means a deficient energy level leading to tiredness and sluggishness.
• Poor immunity
  Not getting enough carbohydrate means not getting the essential vitamins and minerals found in carbohydrates foods, so the immune and other systems will suffer.
• Increased Risk of Heart Disease.
  When carbohydrate is lacking, one is likely to be eating increased amounts of foods high in fat and cholesterol to replace the missing carbohydrates leading to increased risk of heart disease.
• Death from starvation
  An extremely prolonged carbohydrate deficiency could even result in death, due to starvation.

Recommendations

Between 40% and 60% of daily total calories should come from carbohydrates, preferably complex carbohydrates (starches) and natural sugars.
This means;

• Vegetables:
  3-5 servings daily. A serving size is; 1 cup raw, 1/2 cup cooked, 3/4 cup juiced.
• Fruits:
  2-4 servings daily. A serving size is; 1 fist-size fresh, 1/2 cup canned or chopped, 3/4 cup juiced.
• Breads and cereals:
  5-11 servings daily. A serving size is; 1-2 oz bread slice(s), 1 fist size bread roll, 1/2 cup of cooked rice, pasta, grains; beans, lentils, or peas.
• Dairy:
  1-2 servings daily. A serving size is; 1 cup of skim or low-fat milk.

References Dietary Guidelines for Americans 2010. 7th ed. Rockville, MD: United States Department of Health and Human Services and United States Department of Agriculture; 2010.